"The last two years were probably the worst gardening seasons on record, but this year we’ve got a bit of an ideal storm," said Joclyn Silezin, B&Q’s horticultural-category manager.

Garden Centre Association chairman Will Armitage said: "Easter went very well indeed compared to the same weekend last year. Armitage's year-to-date sales are 20 per cent ahead of 2013 with outdoor plants our best-seller."

Buckingham Garden Centre and Nurseries publicity manager Chris Day said it had been a "cracking Easter" with good weather. He said there was a movement to shrubs and more structural plants this year because of more house-building and confidence among shoppers to make bigger purchases.

He added that lawncare products and aphid controls had sold well, as had grow-your-own and alpines.

Day said the centre was looking at its best season since 2010 or 2011.

He believes the influence of new BBC2 show Big Allotment Challenge has encouraged customers: "They're saying the programme inspired them to get out in their garden," he said.

Easom added that TV adverts for Westland products had also increased that brand's sales.

Bransford Webbs managing director Geoff Caesar said: "The thing that's different about this year is it started well and stayed good. Garden centres got stocked up and they stayed stocked up. With Easter being a bit later we didn't have the crazy two weeks beforehand we’ve seen in the past. It's been nice and steady for six weeks or more."

Easter Sunday was rain-hit in the south but the HTA is continuing with a campaign to stop the "bonkers" law that stops garden centres opening on the day.

HTA horticulture head Raoul Curtis-Machin said: "We’re in discussions with a couple of MPs. They are taken aback that the archaic law is still in action. We want to get the Department of Business, Innovation and Skills to turn the law around."

He appeared on TV over the weekend to appeal for the law to change. Curtis-Machin said an exemption for garden cenrtes or an ‘Olympic-style’ exepemtion for normal Sunday opening rather than the current six hour restriction from March to July would end the "bonkers" situation.

The HTA is set to meet Conservative MP Philip Davies, vice-chairman of the All Party Parliamentary Retail Group, who said: "I would like to scrap the Sunday trading restrictions altogether. The sky has not fallen in Scotland where there are no such rules.

"The sky has not fallen in Scotland where there are no such rules. We are living with a ridiculous anomaly. If people want to keep Sunday special that is fine, they can do so. It is about freedom of choice.’ "

Under the Sunday Trading Act 1994 shops of over 300,000 sq ft can only open for a maximum of six hours on a Sunday and not before 10am.

Davies believes that with the growth of online shopping, the time is right for a change.

He intends this week to table a series of amendments to the Deregulation Bill going through Parliament, with MPs being given a chance for a free vote before the summer.

These will include options to abolish restrictions altogether, to allow extra hours for stores to open on Sundays, or to give local authorities the power to decide.

An amendment allowing large garden centres to open for eight hours on Sundays is also expected.

Asda, Morrisons and Selfridges have now told ministers they would like the extra opening hours to be permanent.

DIY store B&Q supports the principle but is not campaigning.

However, the Home Retail Group – which includes Homebase, Argos and Habitat – Sainsbury’s and Waitrose is against any change.

The Department for Business said there were no current plans for a relaxation of the regulations.